Here is the full list of all 31 The Dark Eye: Memoria achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Do You Like Riddles?
Find the Caverns of Fail.
Give all items to Xerxes.
Throw all items into the chasm.
Stone, dust, stone, dust.
Does Bryda know who you really are?
Do you have the guts to start an argument?
Tread lightly.
Try to tear down the wall with the golem.
Catch the rabbit at the first try.
Persuade the spirit of air to help you straight away.
Make your decision.
Complete Chapter Eight.
Complete Chapter Seven.
Complete Chapter Six.
Complete Chapter Five.
Collect all elementals.
Adjust the horns towards the spheres.
Complete Chapter Four.
Ashes to ashes, stone to dust.
Complete Chapter Three.
Find the fox within the labyrinth.
Defeat the spider.
The forest is my home.
Complete Chapter Two.
Give Bryda the wrong astral accumulator.
Shards crack loudly.
Find out who of the adventuring party lies at the first try.
Turn the pig on the grill.
Complete Chapter One.